Bioethics Blogs

Accessibility of trial reports for drugs stalling in development: a systematic assessment of registered trials

Non-publication of clinical trial results has been recognized as a serious scientific and ethical problem. Underreporting frustrates evaluation of a drug’s utility and safety, and fails to redeem the sacrifice of trial participants.

Thus far, policy measures to counteract non-publication have focused on trials of interventions used in practice. However, 9/10 interventions entering clinical testing never achieve marketing licensure. What happens to the results of those trials?

Figure depicting the rates of publication of trials of licensed drugs compared with trials of stalled drugs–overall and by major subgroup.

In our most recent publication, my colleagues and I systematically quantified the proportion of trials of unlicensed interventions that are not published.

We used clinicaltrials.gov trial registration records to create a sample of clinical trials of drugs that achieved licensure between 2005 and 2009 (“licensed drugs” or “translated drugs”) and drugs that stalled in clinical development (“stalled drugs”) in the same time period. Our sample included registered phase II, III or IV trials that closed between January 1st, 2006 and December 31st, 2008 and tested a drug in the treatment of cancer, cardiovascular disease or neurological disorders. We felt this sample provided a relevant and contemporary look into a wide swathe of drug development activity. We then searched Google Scholar, PubMed and Embase, and contacted investigators to determine the publication status of each trial in our sample at least 5 years after reported primary endpoint collection.

Whereas 75% (72/96) of registered trials of licensed drugs were published, only 37% (30/81) trials of stalled drugs were published. The adjusted hazard ratio for publication was 2.7 (95% confidence interval 1.7 to 4.3) in favour of licensed drug trials–that is, clinical trials of licensed drugs were almost three times as likely to publish findings as trials of stalled drugs.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.